DNA methylation (DNAm) plays diverse roles in human biology, but this dynamic epigenetic mark remains far from fully characterized. Although earlier studies uncovered loci that undergo age-associated DNAm changes in adults, little is known about such changes during childhood. Despite profound DNAm plasticity during embryogenesis, monozygotic twins show indistinguishable childhood methylation, suggesting that DNAm is highly coordinated throughout early development. Here we examine the methylation of 27,578 CpG dinucleotides in peripheral blood DNA from a cross-sectional study of 398 boys, aged 3-17 yr, and find significant age-associated changes in DNAm at 2078 loci. These findings correspond well with pyrosequencing data and replicate in a second pediatric population (N = 78). Moreover, we report a deficit of age-related loci on the X chromosome, a preference for specific nucleotides immediately surrounding the interrogated CpG dinucleotide, and a primary association with developmental and immune ontological functions. Meta-analysis (N = 1158) with two adult populations reveals that despite a significant overlap of age-associated loci, most methylation changes do not follow a lifelong linear pattern due to a threefold to fourfold higher rate of change in children compared with adults; consequently, the vast majority of changes are more accurately modeled as a function of logarithmic age. We therefore conclude that age-related DNAm changes in peripheral blood occur more rapidly during childhood and are imperfectly accounted for by statistical corrections that are linear in age, further suggesting that future DNAm studies should be matched closely for age.

The epigenetic processes that regulate antibody secreting plasma cells are not well understood. Here, analysis of plasma cell differentiation revealed DNA hypomethylation of 10% of CpG loci that were overrepresented at enhancers. Inhibition of DNA methylation enhanced plasma cell commitment in a cell division-dependent manner. Examination of in vivo differentiating B cells stratified by cell division revealed a 5-fold increase in mRNA transcription coupled to DNA hypomethylation. Demethylation occurred first at binding motifs of NF-κB and AP-1 and later at those for IRF and Oct-2, and were coincident with activation and differentiation gene expression programs. These data provide mechanistic insight into the cell-division coupled transcriptional and epigenetic reprogramming and suggest DNA hypomethylation reflects the cis-regulatory history of plasma cell differentiation.

Systemic lupus erythematosus (SLE) is characterized by the expansion of extrafollicular pathogenic B cells derived from newly activated naïve cells. Although these cells express distinct markers, their epigenetic architecture and how it contributes to SLE remains poorly understood. To address this, we determined the DNA methylomes, chromatin accessibility and transcriptomes from five human B cell subsets, including a newly defined effector B cell subset from SLE and healthy subjects. Our data define a differentiation hierarchy between the subsets and elucidate the epigenetic and transcriptional differences between effector and memory B cells. Importantly, an SLE molecular signature was already established in resting naïve cells and was dominated by accessible chromatin enriched in AP-1 and EGR transcription factor motifs. Together, these factors acted in synergy with T-BET to shape the epigenome of expanded SLE effector B cell subsets. Thus, our data define the molecular foundation of pathogenic B cell dysfunction in SLE.

BackgroundTriple Negative subset of (TN) Breast Cancers (BC), a close associate of the basal-like subtype (with limited discordance) is an aggressive form of the disease which convey unpredictable, and poor prognosis due to limited treatment options and lack of proven effective targeted therapies.MethodsWe conducted an expression study of 240 formalin-fixed, paraffin-embedded (FFPE) primary biopsies from two cohorts, including 130 TN tumors, to identify molecular mechanisms of TN disease.ResultsThe annotation of differentially expressed genes in TN tumors contained an overrepresentation of canonical Wnt signaling components in our cohort and others. These observations were supported by upregulation of experimentally induced oncogenic Wnt/β-catenin genes in TN tumors, recapitulated using targets induced by Wnt3A. A functional blockade of Wnt/β-catenin pathway by either a pharmacological Wnt-antagonist, WntC59, sulidac sulfide, or β-catenin (functional read out of Wnt/β-catenin pathway) SiRNA mediated genetic manipulation demonstrated that a functional perturbation of the pathway is causal to the metastasis- associated phenotypes including fibronectin-directed migration, F-actin organization, and invasion in TNBC cells. A classifier, trained on microarray data from β-catenin transfected mammary cells, identified a disproportionate number of TNBC breast tumors as compared to other breast cancer subtypes in a meta-analysis of 11 studies and 1,878 breast cancer patients, including the two cohorts published here. Patients identified by the Wnt/β-catenin classifier had a greater risk of lung and brain, but not bone metastases.ConclusionThese data implicate transcriptional Wnt signaling as a hallmark of TNBC disease associated with specific metastatic pathways.

The differentiation of CD8 T cells in response to acute infection results in the acquisition of hallmark phenotypic effector functions, however the epigenetic mechanisms that program this differentiation process on a genome-wide scale are largely unknown. Here we report the DNA methylomes of antigen-specific naïve and day 8 effector CD8 T cells following acute LCMV infection. During effector CD8 T cell differentiation, DNA methylation was remodeled such that changes in DNA methylation at gene promoter regions negatively correlated with gene expression. Importantly, differentially methylated regions (DMRs2) were enriched at cis-elements, including enhancers active in naïve T cells. DMRs were associated with cell type-specific transcription factor binding sites, and these transcription factors clustered into modules that define networks targeted by epigenetic regulation and control of effector CD8 T cell function. Changes in the DNA methylation profile following CD8 T cell activation, revealed numerous cellular processes, cis-elements, and transcription factor networks targeted by DNA methylation. Together, the results demonstrated that DNA methylation remodeling accompanies the acquisition of the CD8 T cell effector phenotype and repression of the naïve cell state. These data therefore provide the framework for an epigenetic mechanism that is required for effector CD8 T cell differentiation and adaptive immune responses.

Multiple myeloma is a malignancy of antibody-secreting plasma cells. Most patients benefit from current therapies, however, 20% of patients relapse or die within two years and are deemed high risk. Here we analyze structural variants from 795 newly-diagnosed patients as part of the CoMMpass study. We report translocations involving the immunoglobulin lambda (IgL) locus are present in 10% of patients, and indicative of poor prognosis. This is particularly true for IgL-MYC translocations, which coincide with focal amplifications of enhancers at both loci. Importantly, 78% of IgL-MYC translocations co-occur with hyperdiploid disease, a marker of standard risk, suggesting that IgL-MYC-translocated myeloma is being misclassified. Patients with IgL-translocations fail to benefit from IMiDs, which target IKZF1, a transcription factor that binds the IgL enhancer at some of the highest levels in the myeloma epigenome. These data implicate IgL translocation as a driver of poor prognosis which may be due to IMiD resistance.

Gain of chromosome 1q (+1q) is commonly identified in multiple myeloma and has been associated with inferior outcomes. However, the prognostic implication of +1q has not been evaluated in the setting of standard triplet regimens. We retrospectively analyzed 201 consecutive patients with newly diagnosed myeloma who received induction with lenalidomide, bortezomib, and dexamethasone (RVD) and were tested for +1q at diagnosis by fluorescent in-situ hybridization. Patients with +1q (n = 94), compared to those without +1q (n = 107), had shorter median progression-free survival (PFS) (41.9 months vs 65.1 months, p = 0.002, HR = 1.90) and overall survival (median not reached (NR) for either arm, p = 0.003, HR 2.69). In subgroup analyses, patients with co-occurring +1q and t(4;14), t(14;16) or del(17p) or with 4 or more copies of 1q had significantly worse PFS (25.1 months and 34.6 months, p < 0.001 and p = 0.0063, respectively), whereas patients with three copies and no other high-risk cytogenetic abnormalities had no significant difference in PFS. These data suggest that when treated with RVD induction, patients with +1q should be considered at very high risk for early progression in multiple myeloma when ≥4 copies are detected or in the context of other high-risk cytogenetic abnormalities.

Epigenetic remodeling is required during B cell differentiation. However, little is known about the direct functions of epigenetic enzymes in Ab-secreting cells (ASC) in vivo. In this study, we examined ASC differentiation independent of T cell help and germinal center reactions using mice with inducible or B cell-specific deletions of Following stimulation with influenza virus or LPS,-deficient ASC poorly proliferated and inappropriately maintained expression of inflammatory pathways, B cell-lineage transcription factors, and Blimp-1-repressed genes, leading to fewer and less functional ASC. In the absence of EZH2, genes that normally gained histone H3 lysine 27 trimethylation were dysregulated and exhibited increased chromatin accessibility. Furthermore, EZH2 was also required for maximal Ab secretion by ASC, in part due to reduced mitochondrial respiration, impaired glucose metabolism, and poor expression of the unfolded-protein response pathway. Together, these data demonstrate that EZH2 is essential in facilitating epigenetic changes that regulate ASC fate, function, and metabolism.